The joint review panel’s public hearings on Benga Mining Ltd.’s proposed Grassy Mountain project concluded Dec. 2 with interested parties arguing for and against the open-pit mine.
One of the concluding topics, which took up the last week of November, centred on the effect mining could have on sensitive populations of westslope cutthroat trout.
Westslope cutthroat trout — also known as cutties — are officially classified as a threatened species by the Canadian government.
Cutthroat trout used to be widespread throughout the upper Bow and Oldman rivers. Eighty per cent of population numbers have been reduced through over-fishing, habitat destruction and intermixing with non-native species like rainbow trout.
Remaining groups of genetically pure cutthroat are limited to isolated groups living in headwater locations like Gold Creek, right next to Grassy Mountain. The Gold Creek population, said aquatic ecologist David Mayhood, is estimated to be the largest of 51 groups in Alberta.
“The Gold Creek westslope cutthroat trout population is crucially important to the overall recovery of the species in Alberta,” Mr. Mayhood said.
Opponents of the project point to the risk of pollution the mine poses, which would harm not only the fish but freshwater access to communities downstream. The risk is especially relevant, given that a few mountains over in British Columbia, Teck Resources was fined $1.4 million in 2017 after a treatment plant’s wastewater leaked into an Elk River tributary.
A specific concern associated with mining is selenium pollution. Selenium is an element found in the earth’s crust. When open-pit mining removes layers of rock to get to the coal, selenium in the piles of waste rock can be exposed to water and air and can leach into the surrounding environment.
High levels of selenium have been found downstream from Teck mines in the Elk Valley, contributing to deformities in cutthroat trout and an estimated 90 per cent drop in population numbers.
Benga’s application, however, assured the joint review panel that Grassy Mountain would learn from Teck’s mistakes.
To prevent water pollution, no water would be released into Gold Creek. Water used in the mining process would be treated and placed in sedimentation ponds before safely entering Blairmore Creek.
A saturated backfill zone, or SBZ, would also be used to prevent selenium pollution. Waste rock would be stored in a lined, submerged pit to allow selenium to undergo natural biogeochemical reactions.
The reactions form selenite, which can then be absorbed into the submerged minerals or solidify as clumps of selenium that remain trapped in the SBZ.
Benga is also willing to construct an engineered gravel-bed reactor (a sort of man-made pond that works like an SBZ) and a selenium water treatment plant.
In the unlikely event that selenium leaches out, studies show the seepage rate is one to two metres a month, giving Benga enough time to react before selenium enters the creeks.
Monitoring in the Oldman reservoir will also mitigate risk to downstream communities.
The real issue facing the westslope cutthroat trout, said Benga’s vice president of external relations, Gary Houston, is the current state of their habitat.
Habitat disruption from previous mining and logging developments, segregated pools and an altered creek path from flooding, as well as cattle grazing and frequent off-highway vehicle use, were the main causes for decreasing trout numbers.
Such threats, Mr. Houston said, could not be properly addressed without external intervention, and reclamation plans would improve cutthroat habitat by increasing creek connectivity and overwintering areas.
“The westslope cutthroat trout in Gold Creek are surviving, but they are not thriving,” he said. “We are confident that the outcome [of reclamation] will result in a more resilient stock.”
Environmentalists, however, aren’t so sure.
Benga estimates mining activity will reduce Gold Creek’s flow by 12 per cent and Blairmore Creek’s by 26 per cent. Reclamation plans are expected to lighten permanent decreases in creek flow to six per cent for Gold Creek and nine per cent for Blairmore Creek, but any reduction, said Mr. Mayhood, would harm the sensitive cutthroat population.
“It is not possible to divert water, critical habitat for every known fish, out of Gold Creek watershed and still have it as habitat in the creek,” Mr. Mayhood said.
Geochemist Jon Fennell, who has experience working on multiple development projects around the world, also expressed doubt over Benga’s plans to avoid leaching selenium pollution.
“I don’t know how you can possibly capture every drop when you have unlined water bodies and rock dumps sitting on top of fractured bedrock in elevated locations and in some cases directly on top of upland springs and tributary streams,” he said.
Part of the issue with Benga’s cutthroat trout plans was an insufficient amount of data regarding fish numbers and spawning habitat.
In its 2016 surveying, Benga noted roughly 1,600 westslope cutthroat trout in Gold Creek and just over 3,200 in Blairmore Creek. Benga utilized electrofishing surveying, which involves using two electrodes to deliver a direct current at high-voltage through the water.
When a fish encounters the electric current, muscular convulsions force the fish to swim towards the positive electrode, where they are caught with a net. The method is relatively safe, with the fish returning to normal within two minutes, but worry of inflicting unnecessary levels of stress on the fish caused Benga to forgo an exhaustive survey of the entire length of both creeks.
As a result, Benga’s application provided no information on juvenile cutthroat numbers of habitation was provided in Benga’s application, and data on spawning habitats for adults was sparse.
“All that we can rely on is the data that you’ve presented, and what that data tells us is of ... seven reaches that you surveyed, you only found spawning fish … in two of those, and in one of those, you only found one pair,” said Mike Sawyer, legal counsel for the Timberwolf Society.
“It seems very thin that you’ve got all these reaches that you’ve designated as spawning habitat, but you haven’t found any spawning fish.”
The lack of information was important because, under the Species at Risk Act, industrial projects that harm protected species and habitat are approved only if there is a low probability of failure or assurances the damage can be reversed.
On top of juvenile populations and spawning areas, the effects of upland vegetation loss and the influence of the sedimentation ponds on water temperature were not addressed by Benga, raising questions with the federal Department of Fisheries and Oceans.
“Overall, the proponent has concluded that several pathways of effects have no residual effect. DFO’s opinion is that there is too much uncertainty with the analyses to date to support these conclusions,” said Stephanie Martens, regional manager of the department’s fish and fisheries habitat protection program.
“With the information available to date, DFO is of the opinion that the ... conditions of the Species at Risk Act will likely not be met and that the project has the potential to result in significant adverse effects to westslope cutthroat trout.”
Next steps
With the public hearings of the joint review panel nearing their end, Benga provided its closing statement Dec. 15. All other participants have the opportunity to provide their own statements on Jan. 8., and Benga then has the opportunity to make a final response Jan. 15.
The federal government’s decision on approving the project is not expected to be made until the end of 2021.
